The same effect can keep you from getting the full value from objects. For example, you are allowed to write in your own books. If adding annotations helps you

The same effect can keep you from getting the full value from objects. For example, you are allowed to write in your own books. If adding annotations helps you learn faster, that's probably worth more than the possible loss in value of the book. There might not even be any loss of value if somebody agrees your annotations are useful. And how often do you sell books anyway? There's also no schoolteacher waiting to put you in detention for vandalizing school property.